please please answer this question I will mark you as their brain list explain how
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hey mate,
the focal length is 10 cm.
since the image distance is equal to the object's distance from the lens which is only possible when the object is placed at 2F.
and focal length=half of 2F..
hope this helps
Victor36:
i got it 20 cm by lens formula
u took u positive??
its convex so u becomes negative
yes
but in both the lenses u remains negative
yes but in convex v and f is positive right so by using lens formula you'll add 1/20 and 1/20 instead of subtracting
u are right but u see na u=v
this is only possible when the object is placed on 2f
the answer is 10 only no matter how yoi get it so we both are right :)
yeah
Answered by
0
since it is a convex lens,
u is negative
v is positive
and f is positive aswell
now applying 1/f = 1/v-1/u
1/f = 1/20 - 1/-20
so 1/f = 1/20 + 1/20
2/20 +i/f
therefore f = 10cm-option b
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